The present invention relates to an imaging device, an endoscope apparatus, an imaging method, and the like.
Techniques for optically measuring a three-dimensional shape have conventionally been known, with various methods for the measuring proposed. The proposed methods include: stereoscopic imaging based on a stereoscopic view with both left and right eyes; phase shift by patterned illumination using a sinusoidal pattern and the like; and Time of Flight (TOF) based on time measurement for reflected light.
The stereoscopic imaging can be achieved with a simple mechanism with a stereoscopic optical system used for an imaging system, and thus requires no special illumination mechanisms or illumination control, and also requires no advanced signal processing. Thus, this technique can be suitably implemented in a small space and thus is advantageous in an imaging system that has been progressively downsized recently. For example, the technique can be applied to an end of an endoscope apparatus, to a visual sensor in a small robot, and for various other needs. Such an application is likely to require not only a highly accurate measurement function but also a normal observation function with high image quality. Thus, to ensure a sufficient resolution, it is a common practice to form parallax images on a common image sensor instead of using separate image sensors. The basic idea of the stereoscopic imaging is to obtain a distance to an object based on an amount of parallax between left and right images. If the left and right images fail to be separately formed on the common image sensor, the amount of parallax cannot be detected, and thus the distance information cannot be obtained.
JP-A-2014-28008 discloses an example of a method of separately forming left and right images. Specifically, switching between left and right imaging optical paths is performed along time with a mechanical shutter, so that the left and the right images are obtained. In this method, white light may be used for illumination, for example.
The left and the right images, separately obtained by the method according to JP-A-2014-28008 in a time division manner, can each be used as an observation image.